12 grey inks

Only Diamine Earl Grey among these dozen inks has such poor water resistance that it just washes clearly off the page.

 

Monteverde Smoke Noir and Pennonia Viharfelhő has excellent water resistance; even the driest lines of ink remain high-contrast and sharply defined on the page after a five-minute soak, and in spite of violent water movement as the bucket was being filled. Pilot Iroshizuku Kiri-same and Fuyu-syogun, and GvFC Stone Grey, have good water resistance and remain perfectly legible, despite shedding some colour upon contact with water.

 

Diamine Silver Fox and Herbin Gris Nuage are surprisingly good in that regard, even though they're such light-coloured inks.